[An evolutionary study at 5 years of left ventricular systolic function in patients with an uncomplicated infarct]

The aim of the present study was to compare the left ventricular ejection fraction in a first uncomplicated acute myocardial infarction before hospital discharge (initial ejection fraction) and 5 years later (late ejection fraction) and to evaluate the factors that may influence their possible changes.

Eighty-three patients (mean age: 52.2 +/- 7.5, range: 35-65 years) who had a first uncomplicated infarction were evaluated. Between 10 and 15 days after the acute episode, thallium perfusion scintigraphy, radionuclide ventriculography and coronary arteriography were carried out. The ventricular function was reevaluated after 5 years with radionuclide ventriculography. The population was classified according to the localization of infarction (anterior or inferior) and to the initial ejection fraction (< 30%, 30-50% and > 50%). The factors derived from predischarge exercise test, perfusion scintigraphy, radionuclide ventriculography and coronary arteriography that might have had an influence on ejection fraction changes were evaluated with bivariate and multivariate analysis.

1) left ventricular ejection fraction of anterior infarctions was lower than in inferior infarctions, both during the subacute phase (35.1 +/- 12.9 vs 48.1 +/- 12.1; p < 0.001) and after 5 years (41.3 +/- 15.1 vs 47.6 +/- 12.8; p = 0.006); 2) a significant increase in ejection fraction after 5 years was found in patients with anterior infarction (35.1 +/- 12.9 vs 41.3 +/- 15.1; p < 0.001), particularly in those with initial ejection fraction between 30-50% (38.8 +/- 5.9 vs 44.8 +/- 11.2; p < 0.001), and 3) no variable, either clinical or derived from exercise test, perfusion scintigraphy, radionuclide ventriculography or coronary arteriography, discriminated between the patients in whom ejection fraction decreased by more than 5% during follow-up nor those with anterior infarction and initial ejection fraction between 30-50% in whom ventricular function was improved after 5 years.

Left ventricular ejection fraction of anterior infarctions shows a significant improvement after 5 years, particularly in the subgroups with initial ejection fraction between 30-50%. Predictive factors of such improvement have not been identified.